Pre-manufactured roof plate element and girder thereto

ABSTRACT

A pre-manufactured roof plate element comprising a number of longitudinal box-shaped girders of steel plate, which are upwardly connected with a compressive force plate with almost the same width as the girder, and which preferably are positioned in each side and in the middle of the element. The compressive force plate consists of a corrugated steel plate having a preferably trapezoid shape. A box-shaped girder of the said type is a complement to the roof plate element. A roof plate element or a girder according to the invention may be produced totally without use of organic material.

FIELD OF THE INVENTION

The present invention relates to a pre-manufactured roof plate elementof the type described herein.

BACKGROUND ART

DE-A1-25 20 255 describes a light building element composed ofconstruction elements, in which roofing plates and stiffening constitutean integrated unit, such as a pre-manufactured roof plate element, eachconsisting of at least one open basic profile glued directly on an uppercover plate constituting both covering and load compressive element, andwhere the cover plate is broader than the basic profile and extendsoutside the basic profile along both longitudinal edges.

EP-A1-0 675 990 (WO 92/19826) discloses a premanufactured roof plateelement comprising three boxshaped, carrying basic profiles of steelplate, which upwardly is directly connected with a compressive forceplate consisting of strong construction plywood, and having the samewidth as the basic profiles, which are placed along opposite long sidesand in the middle of the roof plate element.

Common for these known light roof plate elements is, that they have arelative large overall height, which during manufacturing, storage andtransport cause extraordinary large demands for space. Also byprojecting and the construction work it is inexpedient, that the overallheight of the roof plate element itself is large, as it causes extracosts for obtaining extra free height.

The invention has for its purpose to provide an improved premanufacturedroof plate element of the type mentioned in the introductory part, andwhich by means of simple provisions makes it possible to reduce theoverall height of the roof plate element itself.

The roof plate element according to the invention is distinctive in thatsaid compressive force plate consists of a steel plate, which—seen incross section—is corrugated. By means of simple provisions it is herebyobtained, that it becomes possible to reduce the overall height and theweight of the roof plate element, which may result in considerablesavings by transport and storage of finished pre-manufactured roof plateelements. However, it is of most importance that a roof plate elementaccording to the invention may be produced totally without use oforganic material. In order to further reduce the overall height of theroof plate element itself, it may be advantageously, that also a bottomside part of said boxshaped girders—seen in a cross section—also iscorrugated.

In order to give the boxshaped girder by the roof plate elementaccording to the invention better side stability it may beappropriately, that said compressive force steel plate has longitudinal,folded side edges extending downwards along opposite vertical sides ofthe girder.

The roof plate element according to the invention may be such providedthat the corrugation of said compressive force plate is trapezoid, orthe corrugation may be wave-shaped. Besides the same concerns saidbottom side part of the girder. By corrugation of top and bottom sideparts of the girder a better stability is obtained for both upwards anddownwards directed forces in connection with loads and gust of wind.

Furthermore the invention relates to a boxshaped girder of the typementioned in the introductory part of claim 5 by way of example for usein a roof plate element according to the invention, which girder isdistinctive in, that the compressive force plate consists of a steelplate, which—seen in cross section—is corrugated.

The overall height of the girder according to the invention may befurther reduced, if the girder is such provided, that a bottom side partof said boxshaped girders—seen in cross section—also is corrugated.

In order to further improve the load capacity and the side stability ofthe girder according to the invention, it may be advantageously be suchprovided, that said compressive force steel plate has longitudinal,folded side edges extending downwards along opposite vertical sides ofthe girder.

The girder according to the invention is preferably such provided thatthe corrugation of said compressive force plate is trapezoid, or saidcorrugation of said compressive force plate may be wave-shaped.

The invention is explained in more detail in the following withreference to the drawing, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a known pre-manufactured roof plateelement, cf., EP-A-1-0 675 990(WO92/19826) of the same type as the roofplate element according to the invention,

FIG. 2 shows a view—partly in section—of another known roof plateelement cf. NO-C-148 823 or DE-A1-25 20 255 with boxshaped girder ofsteel plate,

FIG. 3 shows a view—partly in section—of the girder part of the knownroof plate element shown in FIG. 1, while

FIG. 4 shows a corresponding view—partly in section—of an embodiment fora girder by a roof plate element according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Like the roof plate element 3 shown in FIG. 1 and 3, the roof plateelement according to the invention is manufactured with varying span oflength L, which by the known pre-manufactured roof plate element variesfrom about 7,2-14,4 m, and the total thickness varies correspondinglybetween about 0,5-0,35 m which at the time was a considerable reductionof thickness or overall height in relation to the at that time knownroof plate element, cf., FIG. 2, which has a maximum span of about 13,2m thickness of 0,375 m.

In other words the development goes towards reducing the overall heightof such premanufactured light roof plate elements by reducing the heightof the boxshaped girder 5 consisting of electroplated steel plate. Bythe girder cf. FIG. 2 the upper side flanges are connected with theupper cover plywood plate by means of longitudinal laths, which by theroof plate element shown in FIGS. 1 and 3 are substituted by an extraplywood plate having the same width as the box-shaped girder 5, andconstituting a compressive force top plate.

By the embodiment for a premanufactured roof plate element 4 accordingto the invention shown in FIG. 4 the extra compressive force plywoodplate is substituted by a corrugated top plate 6, which as shown has atrapez-corrugation; but which in principle may have any other form ofcorrugation, for instance wave-shaped corrugation.

The top plate 6 has at opposite side edges folded side edges 8, whichgive the top plate extra bending strength and which form a natural sidelimitation of the box-shaped girder 5 of the roof plate element. Theshown side edges 8 may be possibly be avoided, which possibly makes itpossible to use a trapezoid-corrugated steel plate, which just is cut incorrect width with outer horizontal flanges, which are connected tofolded-in side flanges of the box profile of the girder, for instance bymeans of self-cutting screws mounted from the top side of the coverplate 10. Corresponding thereto the shown side edges 8 make it possibleto avoid the folded side flanges of the basic profile of the girder.

As indicated in claim 2 a bottom side part of the girder 5 by the roofplate element 4 according to the invention may be provided with asuitable corrugation, which would make a further reduction of thicknessof the roof plate element possible.

The overall height or thickness of the roof plate element 4 according tothe invention may at a span of about 14 m and with unchanged width ofthe girder 5 be reduced to about 0.2 m. With unchanged width and anoverall height of 0.30 m the roof plate element and respectively thegirder according to the invention may have a span of up to about 20 m.

However, it is of most importance that a roof plate element 4 accordingto the invention may be manufactured totally without use of organicmaterial, that is totally without material, which because of humiditymay be damaged because of rot.

By the known roof plate elements cf. for instance FIGS. 1, 2, and 3 theupper cover plate, usually consisting of plywood, consisting acompressive force plate, or carrying construction element. The same isthe case by the said extra plywood plate by the roof plate element 2shown in FIGS. 1 and 3, which also constitutes an important constructionpart.

Otherwise it is, however, by the roof plate element respectively thegirder according to the invention, where the girder 5 in itselfconstitutes a self-carrying box girder, that is where the upper coverplate 10 is not included as a carrying construction part.

In other words, the girder 5 may be used as an independent lightweightcarrying girder. As shown to the right in FIG. 3, a roof plate element 4may consist of a number of girders 5 (for instance, with a mutualplacing corresponding to FIG. 1) and where upper cover plates 7 areformed by hard insulation plates covered with roofing felt or roofingfoil. Such a roof plate element according to the invention mightdownwardly be covered with, for instance, perforated steel platessecured directly to the underside of the girders 5, and thereby beincluded as carrying part of the roof construction.

What is claimed is:
 1. A pre-manufactured roof plate element comprisinga plurality of longitudinal boxshaped girders, each girder comprisingvertical sides and a bottom side part made of steel plate, each girderbeing upwardly connected with a compressive force plate havingsubstantially the same width as that of the girder, and said girders arepositioned in each side and in the middle of the element, wherein saidcompressive force plate consists of a steel plate which is corrugated.2. A roof plate element according to claim 1, wherein a bottom side partof said boxshaped girders also is corrugated.
 3. A roof plate elementaccording to claim 1, wherein said compressive force steel plate haslongitudinal, folded side edges extending downwards along oppositevertical sides of the girder.
 4. A roof plate element according to claim1, wherein the corrugation of said compressive force plate is trapezoid.5. A girder for by way of example a pre-manufactured roof plate elementaccording to claim 1 and consisting of a boxshaped basic profile ofsteel plate and with an upper compressive force plate, wherein thecompressive force plate consists of a steel plate which is corrugated.6. A girder according to claim 5, where a bottom side part of saidboxshaped girder also consists of a steel plate, which is corrugated. 7.A girder according to claim 5, wherein said compressive force steelplate has longitudinal, folded side edges extending downwards alongopposite vertical sides of the girder.
 8. A girder according to claim 5,wherein the corrugation of said compressive force plate is trapezoid.